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- Conventional Hydro
Side channel evolution and design: achieving sustainable habitat for aquatic species recovery
Lead Companies
Bureau of Reclamation
Lead Researcher (s)
- Nathan Holste
How do side channels form and evolve in both sand and gravel bed river systems? Side channels in natural river corridors are created and maintained as a result of a number of processes related to the morphology and geology of the river corridor and floodplain, the hydrology of the watershed, the sediment supply and size, and the amount of large wood within the system. A global understanding of how side channels form and evolve over time currently does not exist. To achieve this understanding of side channel form and process, we propose to conduct an empirical study of side channels across the variety of river systems represented in our study areas. This study would evaluate a range of variables that characterize side channels in terms of their form, location and angle of inlet from the main stem of the river, their frequency of inundation (perennial to intermittent), the type of habitat they provide (target species life stage served) as well as their evolution over time. The outcome of this study would be a classification of side channels and a conceptual model describing the side channel life cycle.
Technology Application
Conventional Hydro
Research Category
Environmental and Sustainability
Research Sub-Category
Fish and Aquatic Resources
Status
ongoing
Completion Date
2022
- Conventional Hydro
Side channel evolution, geomorphic diversity, and sediment transport on the Bighorn River following larger dam releases between 2008 and 2018
Lead Companies
Bureau of Reclamation
Lead Researcher (s)
- Melissa Foster
The proposed research will test the following hypotheses and conclusions from previous work: (1) the wetted perimeter of the Bighorn River continues to remain relatively stable since dam emplacement, as found in a previous study; (2) geomorphic diversity within the channel is likely stable since the previous study and any recent erosion within the channel does not fall outside of historic fluctuations (3) physical excavation is required to reconnect many endangered and disconnected side channels along the Bighorn River, as model predictions indicate that the side channels will not be reconnected with high flows alone; (4) once restored, high flow releases can help prevent aggradation at side channel entrances.
Technology Application
Conventional Hydro
Research Category
Environmental and Sustainability
Research Sub-Category
Shoreline and Riparian Resources
Status
ongoing
Completion Date
2020
- Conventional Hydro
Simulating California’s water supply system under future climate stresses
Lead Companies
Bureau of Reclamation
Lead Researcher (s)
- Michael Wright
Our main water supply model is calibrated to the historical record; we should calibrate it to climate model outputs, too. In S&T 1816 we developed climate models with this purpose in mind. We can generate weather on a monthly time scale and stress the current water supply system with realistic rainfall and snow distributions derived from future scenarios. We can find out how the system would respond to a drought or a whiplashing climate. This kind of modeling could inform decision-making about projects like dams with long operational lives.
Technology Application
Conventional Hydro
Research Category
Environmental and Sustainability
Research Sub-Category
Water Resources
Status
ongoing
Completion Date
2022
- Conventional Hydro
Simulation, Analysis and Mitigation of Vortex Rope Formation in the Draft Tube of Hydraulic Turbines
Lead Companies
The Pennsylvania State University
Lead Researcher (s)
- Hosein Foroutan
Flow in the draft tube of a hydraulic turbine operating under off-design conditions is very complex. The instability of the swirling flow may lead to the formation of a helical precessing vortex called the “vortex rope”. The vortex rope causes efficiency reduction, severe pressure fluctuation, and even structural vibration. The primary objectives of the present study are to model and analyze the vortex rope formation using high fidelity numerical simulations. In particular, this work aims to understand the fundamental physical processes governing the formation of the vortex rope, and to investigate the capability of turbulence models to simulate this complex flow. Furthermore, mitigation of the vortex rope formation is addressed. Specifically, a vortex rope control technique, which includes injection of water from the runner crown tip to the inlet of the draft tube, is numerically studied. A systematic approach is considered in this study starting from the simplest and advancing towards the most complicated test case. First, steady simulations are carried out for axisymmetric and three-dimensional grids in a simplified axisymmetric geometry. It is shown that steady simulations with Reynolds-averaged Navier-Stokes (RANS) models cannot resolve the vortex rope, and give identical symmetric results for both the axisymmetric and three-dimensional flow geometries. These RANS simulations underpredict the axial velocity by at least 14%, and turbulent kinetic energy (TKE) by at least 40%, near the center of the draft tube even quite close to the design condition. Moving farther from the design point, models fail in giving the correct levels of the axial velocity in the draft tube. This is attributed to the underprediction of TKE production and diffusion near the center of the draft tube where the vortex rope forms. Hence, a new RANS model taking into account the extra production and diffusion of TKE due to vortex rope formation is developed, which can successfully predict the mean flow velocity with as much as 37% improvements in comparison with the realizable k-ε model. Then, unsteady simulations are performed, where it is concluded that Unsteady RANS (URANS) models cannot capture the self-induced unsteadiness of the vortex rope, but instead give steady solutions. The hybrid URANS/large eddy simulation (LES) models are proposed to be used in unsteady simulations of the vortex rope. Specifically, a new hybrid URANS/LES model in the framework of partially-averaged Navier-Stokes (PANS) modeling is developed. This new model is one of the main contributions of the present study. The newly developed PANS model is used in unsteady numerical simulations of two turbulent swirling flows containing vortex rope formation and breakdown, namely swirling flow through an abrupt expansion and the flow in the FLINDT draft tube, a model-scale draft tube of a Francis turbine. The present PANS model accurately predicts time-averaged and root-mean-square (rms) velocities in the case of the abrupt expansion, while it is shown to be superior to the delayed detached eddy simulation (DDES) and shear stress transport (SST) k-ω models. Predictions of the reattachment length using the present model shows 14% and 23% improvements compared to the DDES and the SST k-ω models, respectively. For the case of the FLINDT draft tube, four test cases covering a wide range of operating conditions from 70% to 110% of the flow rate at the best efficiency point (BEP) are considered, and numerical results of PANS simulations are compared with those from RANS/URANS simulations and experimental data. It is shown that RANS and PANS both can predict the flow behavior close to the BEP operating condition. However, RANS results deviate considerably from the experimental data as the operating condition moves away from the BEP. The pressure recovery factor predicted by the RANS model shows more than 13% and 58% overprediction when the flow rate decreases to 91% and 70% of the flow rate at BEP respectively. Predictions can be improved dramatically using the present unsteady PANS simulations. Specifically, the pressure recovery factor is predicted by less than 4% and 6% deviation for these two operating conditions. Furthermore, transient features of the flow that cannot be resolved using RANS/URANS simulations, e.g., vortex rope formation and precession, is well captured using PANS simulations. The frequency of the vortex rope precession, which causes severe fluctuations and vibrations, is well predicted by only about 2.7% deviation from the experimental data. Finally, the physical mechanism behind the formation of the vortex rope is analyzed, and it is confirmed that the development of the vortex rope is associated with formation of a stagnant region at the center of the draft tube. Based on this observation, a vortex rope elimination method consisting of water jet injection to the draft tube is introduced and numerically assessed. It is shown that a small fraction of water (a few percent of the total flow rate) centrally injected to the inlet of the draft tube can eliminate the stagnant region and mitigate the formation of the vortex rope. This results in improvement of the draft tube performance and reduction of hydraulic losses. Specifically in the case of the simplified FLINDT draft tube, the loss coefficient can be reduced by as much as 50% and 14% when the turbine operates with 91% and 70% of the BEP flow rate, respectively. In addition, reduction (by about 1/3 in the case with 70% of BEP flow rate) of strong pressure fluctuations leads to more reliable operation of the turbine.
Technology Application
Conventional Hydro
Research Category
Powerhouse Equipment
Research Sub-Category
Turbine
Status
complete
Completion Date
2015
- Small or Non Conventional Hydro
Small Hydro Interconnection Benchmarking
Lead Companies
Pacific Northwest National Laboratory
Lead Researcher (s)
- Travis Douville
Deployment of distributed energy resources (DERs) has increased in recent years and is anticipated to continue growing in the future. Small hydropower is one of the DERs that is projected to rise, and as this resource grows there is a need for utilities and regulators to consider interconnecting them to the main grid. Connecting DERS to the grid may allow utilities to better manage peak demand, avoid transmission overloads and keep electricity flowing to the customers. An emerging application for renewable DERs is resilience – providing power if a site loses grid electricity. Although these upgrades have the potential to improve resilience, a barrier to their execution are distribution and transmission interconnection processes which have been described as prolonged, opaque, and inconsistent by applicants. On the other hand, utility owners have struggled to understand how to limit strains on both the distribution and transmission grid. To address this gap, a national dataset was developed to summarize different cost drivers and required work that are associated with hydropower projects. This study aims to build a shared understanding that will enhance project selection, limit stranded costs, and benefit interconnection customers as well as the system operators, and ultimately energy consumers. The focus of this study is to find trends within three major queue owners, PJM, PacifiCorp, and Idaho Power Company (IPC) and investigate how network upgrades associated with conductoring, line protection and control, substation modification and construction, and communication infrastructure have an effect on project timeline and cost. This will also help up compare the three different queues and analyze the trends within each one.
Technology Application
Small or Non Conventional Hydro
Research Category
Interconnect Integration and Markets
Research Sub-Category
Future Grid
Status
ongoing
Completion Date
TBD
- Marine Energy
Smart Node – A Highly Adaptable Passive Acoustic Receiver System
Lead Companies
Pacific Northwest National Laboratory
Lead Researcher (s)
- Daniel Deng
Technology Application
Marine Energy
Research Category
Environmental and Sustainability
Research Sub-Category
Environmental Impact
Status
ongoing
Completion Date
TBD
- Marine Energy
SNL Support for Kearns and West FOA 1837
Lead Companies
Sandia National Laboratories
Lead Researcher (s)
- Jesse Roberts
The few wave and tidal (i.e., MHK) projects that have been licensed and permitted in the United States have been challenged by a lack of a clear understanding of potential environmental effects and mutual understanding of the regulatory pathway. Due to the low number of installed and operating projects, regulators across federal, state, and local jurisdictions in many regions are relatively unfamiliar with MHK technologies, their potential environmental effects and available strategies for mitigation and monitoring. Additionally, the developers themselves, who are typically responsible for framing the project for regulators, often lack the information and tools for establishing a productive dialog with regulators. This project compiles existing environmental information from wide ranging data sources which are currently difficult to find across several sources. Further, by engaging with experts, both nationally and internationally, across academic, government, non-profit and industry sectors the information is brought into a suite of tools, i.e., the Toolkit. The Toolkit will be accessible via the project’s web Portal where environmental information relevant to a potential project site and topics of interest can be readily accessed in support of the most expeditious permitting process, especially to address regulatory needs.
Technology Application
Marine Energy
Research Category
Environmental and Sustainability
Research Sub-Category
Regulatory Process
Status
ongoing
Completion Date
2022
- Marine Energy
SNL Wave-SPARC Prize Support
Lead Companies
Sandia National Laboratories
Lead Researcher (s)
- Jesse Roberts
The goal of this WaveSPARC prize scoping project to maximize the beneficial impact of a thriving WaveSPARC community. This prize may be funded in the near future. Diligent prize preparation under a formal prize is necessary but not sufficient. Thorough derisking of the most challenging and novel elements of the prize and setting the groundwork for the prize to achieve its core values is essential. WaveSPARC has been a lab-led effort since 1 October 2014 focused on spurring early-stage marine energy innovation that can be further developed by industry for commercial applications. WaveSPARC provides innovation and assessment tools to support grid-scale wave energy converter (WEC) design concepts with high technology performance levels and low technology readiness levels. It has developed publicly accessible techno-economic assessment tools, novel WEC concepts, and functional requirements for WEC arrays. By introducing a WaveSPARC Prize, the publicly available and well-received tools created by WaveSPARC would be further propagated and utilized by those within the marine energy industry, as well as associated industries such as materials and soft robotics, among others. The prize would also help spur innovation and collaboration in WEC designs that follow WaveSPARC methodologies.
Technology Application
Marine Energy
Research Category
Technology
Research Sub-Category
Wave
Status
ongoing
Completion Date
Expected 2022
- Conventional Hydro
Software Tool Development to Generate Stochastic Hydraulic Simulations using HEC-RAS
Lead Companies
Bureau of Reclamation
Lead Researcher (s)
- Ari Posner
Implementation of this project will facilitate implementation of probabilistic modeling and reduce time required to implement them, by several orders of magnitude. Stochastic simulation and representation of modeling results as probabilistic is a growing field and identified as an important and valuable effort in many fields of science and engineering (Romanowicz & Beven,1996, 1998, 2003; Aronica et. al., 1998, 2002; Bates et. al., 2004; Hall et. al., 2005; Pappenberger et. al., 2005, 2006). Probabilistic modeling is required for most risk analyses associated with large infrastructure projects. Development of this tool will allow HEC-RAS modelers from the most sophisticated regional efforts to the most simple project implemented at the most local level to enter their calibrated and validated model into this software tool and produce probabilistic results, by doing nothing more than putting in the location of their model program file. This tool could save on the order of weeks of time for any project to develop probabilistic results.
Technology Application
Conventional Hydro
Research Category
Interconnect Integration and Markets
Research Sub-Category
Hydraulic Optimization
Status
ongoing
Completion Date
2021
Don’t see your waterpower research?
Have questions about WaRP?
Contact Marla Barnes at: marla@hydro.org